JAXB binding customization syntax reference is online
I just posted the reference of the complete JAXB binding customization elements. This is the latest addition to the user support resources for JAXB.
This documentation is generated from XML Schema automatically by using xnsdoc, which kindly offers free licenses for eligible open source projects (if you know of any good free software for doing this, let me know!)
Since the original schema doesn't have not enough comment, this generated documentation doesn't have too much human readable description either. I plan to spend some time on improving that. In the mean time, at least this should serve you as an authoritative syntactic reference.